The present invention relates to digital signal processing and in particular to embedded firmware or software in a smartphone to compensate for lost gain where headroom is required for digital signal processing.
Digital signal processing technologies are often applied in a smartphone before a master volume control and such digital signal processing technologies may require creating digital headroom which reduces overall gain, and as a result, system volume is reduced. Making up for the reduced gain often requires pushing the signal to clipping, or through a hard limiter with look-ahead, or compressor with residual clipping on transients. The use of limiters and compressors to reduce the dynamic range of the signal often further introduces artifacts (distortion and level oscillations—“pumping” artifacts) into the audio signal.